Block-signal system.



Patented June 15, 1909.

F. RHEA. B'LOGK SIGNAL SYSTEM.

APPLICATION FILED APR. 6, 1909.

lnvenor mm M y Abh'y.

UNITED STATES PATENT opinion,

FRANK RHEA, OF SOHENEOTADY, NEW YORK, ASSIGNOR TO GENERAL'ELECTRIOCOMPANY, A CORPORATION OF NEW YORK.

BLOCK-SIGNAL SYSTEM.

Specification of Letters Patent.

liatented June 15, reps,

Application filed April 6, 1909. Serial No. 488,271.

, To all whom it may concern:

Be it known that I, FRANK Rana, a citizen of the United States, residimat Schenectady, count-y of Schenectady, tate of New York, have inventedcertain new and useful Improvements in Block-Signal Systems, of whichthe following is a specification.

My invention relates to alternating current block signal systems forelectric roads, and its object is to provide means for reducing thenumber of track circuits ordinarily required for the roper control ofsignalindications, particu arly at cross-overs, sidings, etc. It isordinarily the practice to rovide separate track circuits for each signaoperation, and this practice often results in producing a large numberof short traclr circuits. In alternating current systems it is desirableto keep the number of track circuits as small as possible. In what isknown as the inductive bond system, each. additional track circuit meanstwo additional bonds, which are expensive, and in any system an extratransformer is required for each additional track circuit and thecurrent consumed is increased. By my invention I am enabled to obtainwith'perfect definiteness at any point on an existing track circuit acontrol of the signalsfby a car passing that point without addinganother track circuit -for accomplishing this result.

My invention consists in inserting at the desired point in the trackcircuit a reactive Winding, and employing the voltage drop in this win(ing for actdating the track relay for initiating an additional signalmovement. 7

' My invention is particularly advanta geous for. use at cros's o'vers,s dings, etc, and may. a so be used advantageously in many other cases,as, for instance, in singletrack operation where it desired' to staggerthe signals, and ivh re the distance between adjacent sijgna s oroperation in the same direction is not greater than can conveniently andefficiently be operated by a single-track circuit.

My invention Wlll best be understood by reference to the, accompanyingdrawing, 1n hich Figure 1 shows diagrammatically a, bin 1,; signalsystem arran ed in accorda' cej with my invention; *ig's. 2 and 3showfmodi fications in the'ai'rangement of the reactive v i Winding.

In Fig. 1, A represents the track rails of an'elect-ric railway. Brepresents a transmission circuit from which the alternating current issupplied to the signal circuits. C represents a transformer having itspri- B, and its secondary connected across the track rails through aresistance or impedance 0, whichserves to limit the current drawn fromthe transformer when a car stands saturation of the transformer byunbalanced power current in the track rails. D and D representconductors cross-connecting the rails on opposite sides of thetransformer C, In practice these conductors would be substantiallyequidistant from the transformer. These conductors form with thetransformer and the track railsclosed track circuits. Relays E and E areplaced at the ends of the two track circuits supplied from transformerC. These relays are shown diagrammatically of the two-phase indncjtiontype, comprising a short-circuited secondary member 8;, which carriesthe relay contacts, a winding c connected in shunt to a short length ofrail adjacent to the crosseonnecting conductor, and a second windng 6supplied with current from the transmission circuit through atransformer F.

transformer O and relay E? a reactive. wind-j mg K is nserted in one ofthe track ra ls. In

shunt to this reactive, windingis connected the track winding e? of the,relay E, whi is co sequently energized by the vQlt tgo ilro in thereactive winding The iin fedanc of the reactive winding Kneednotbelh'rga in fact it need not amount to more than the impedance of one ortwo hundred feet oi a l $1 1 hat s Pr ence n he trac i cu t l e I notmaterially increase the total imp'e'dahce phase controlling device, suchas a co nmary connected to the transmission circuit across itsterminals, and also to prevent the relay E and. puts signal H atFurthermore, the relay does not depriv he rein) E of any current, butmerely utilizes the smell voltage drop due to that current in passing.As many additional reactive coils and relays as d. .Jed may therefore beadded to the track. circu t without impairing the operation of my at theend of the track circuit.

1, I have shown the relay E conne ted for protecting the junctionbetween a branch trecl: or siding: A and the main track A. The branchtrack may or may not he provided with signals.

G represents a contact on the track switch.

E? represents asignstl for the clock extend ing between thecross-connectingconductors I) end D, the direction of trefiic heiugshown This signal H is controlled in my the arrow. the usual manner byrelays E and E i represents 2, signal for the main track at foulingpointlietween the main track and ling. represents at signal for thebranch track for protecting the .iouling point.

When the switch is thrown for the main,

D and l)" is unoccupied, signals H and H are at clear, while the signalH is at stop, its circuit being open at the track switch G A oerentering the block shunts the relay E and puts signal H at stop. It doesnot affect the signal H until it reaches the insulated joint aroundwhich the reactive winding K is connected. As soon, however, as itpasses over this insulsted joint, it shunts stop. E remain shunted untilthe car has passed some distance beyond transformer (3. Before res-clungthis trsnsformer, however, relay E has been shunted so thatneithersignal Il nor H is cleared until the cor hospasscd thecross-connecting conductor D, so that relay E is renergizedi Passinginto the next block, the cor shunts relay E and puts signal H at stop.If a car is on the track A, and. wishes to run onto the main track, thetrack switch is thrown to its other position. The In ovemcnt of theswitch. contact G opens the circuit of signal H and closes the circuitof signal H through the contacts of relsys E and E The signal H istherefore set at stop and signal H is cleared, car run onto the mentie-ell, iel H going to stop as soon as or es the insulated joints atthe end the hrench ire-cl: A.

The particular application of the relay E and. reactive winding K isonly one of many which will be obvious to those skilled in the Bothrelays end rt. It will he observed thet ordinarily, in

l to enters the operation of eciiieci soove, it we winding K inserted onone roll.

ondery winding as indicated on the drawing, and when' ck between thecross-connected con-" scenes the two signals, which is avoided by theuse of the recctive winding and extra relay.

In Fig. 1, I have shown only one reactive It is in general advantageousto employ two windings mounted on s common core and inserted in oppositerails, as indicated in Fig. 2. The advantage of this arrangement is thatthe effect of the power current is opposed in the two windings, so thatthe tendency to saturation is decreased. The relay may be provided withtwo track-windings 0 connected in shunt to the two reactive windings,respectively, so as to be energizer by the voltage drop in both reactivewindings. Instead of impressing the voltage drop in the reactivewindings on the relay windings directly by the shunt connection of Fig.2, it may be impressed indirectl through'an suxilisry secon the core ofthe reactive windings K, as shown in Fig. 3., This orrsngement of Fig. 3hasthe advantage that no powercurrent can reach the relay track winding,but is less efiicient, due to losses in the-magnetic core, through whichthe voltage is induced in the winding is.

I do not desire to limit-myself to the pan ticular construction andarrangement of parts here shown, but aim in the appended claims to coverall modifications which are within the scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, i.s,-

1. In e' block si nal system comprising signals for the blocscs withcontrol circuit-s therefor, a source of alternating current con nectedacross the track, a track relay st :1. distance from the source andsupplied with current therefrom through the track rails, e reactivewinding inserted in the track circuit at a, point intermediate seidrelay and said source, and a track relay energized by the voltage dropin said reactive winding and having its contacts connected in a. controlircuit other than that in which are connectecl the contacts of the firstrelay.

2.. In a block 51' 211 system comprising signals for the bloc s withcontrol circuits therefor, av source of alternating current connectedacross the track, a track relay at a distunes from the source andsupplied with current therefrom'through the track rolls, a reactivewinding in the track circuit at a point intermediate said relay and saidsource,

and a track relay having a Winding connected in shunt to said reactivewinding and having its contacts connected in c control circuit otherthan that in which are connected the contacts of the first relav.

3. In a block s' 8.1 system comprising signals for the bio s withcontrol circuits therefor, a source of alternating current connectedacross the track, a. track'relay at a distance from the source andsupplied with ourcuit at two approximately opposite points intermediatesaid relay and 'sai source, and

a track relay energized by the voltage drop' in both of said reactivewindings and having its contacts connected in a'control circuit otherthan that in which are connected the contacts of the first relay. I

4. In a block signal system comprising signals for the blocks withcontrol circuits therefor, a source of alternating current connectedacross the track, a track relay at a distance from the source andsupplied with current therefrom through the track rails, two reactivewindings mounted on a common magnetic core and inserted in the trackcircuit at two approximately opposite points intermediate said relay andsai source, and a track relay having two windings connected in shunt tothe two reactive windings and having its contacts connected in a controlcircuit other than that in which are connected the contacts of the firstrelay.

5. In combination with an electric railway, a block system in which thetrack circuits are not separated by insulated joints, comprising sourcesof alternating current connected across the rails at intervals,conductors cross-connecting the rails at points between said sources andforming with the sources and the rails closed track circuits,

track relays operatively related to said track circuits at the endsremote from the sources and supplied with current therefrom, a' reactivewinding inserted in a track circuit at a point intermediate the relayand the source, and a track relay energized by the voltage drop in saidreactive winding andfhaving its contacts connected in a control circuitother than that in which are connected the contacts of the relay at theend of the track circuit.

6. In combination with an electric railway,

a block signal system in which the track circuits are not separated byinsulated joints,

comprising sources of alternating current connected across the rails atintervals, conductors cross-connecting the rails at points between saidsources and forming with the sources and the rails closed trackcircuits, track relays operatively related to said track circuits at theends remote from the sources and supplied with current therefrom, areactive winding inserted in a track circuit at a point-intermediate therelay and the source, and a track relay having a winding connected inshunt to said reactive winding and having its contacts connected in acontrol circuit other than that in which are connected the contacts ofthe relay at the end of said track circuit. I

7. In combination with an electric railway, a block signal system inwhich the track circuits are not separated by insulated joints,comprising sources of alternating current connected across the rails atintervals, conductors cross-connecting the rails at points between saidsources and forming with the sources and the rails closed trackcircuits, track relays operatively related to said track circuits at theends remote from the sources and supplied with current therefrom, tworeactive windings ona common magnetic core inserted in a track circuitat two approximately opposite points intermediate said relay and saidsource;' and a track relay energized by the voltagedro'p in both saidreactive windings and having its contacts connected in a control circuitother than that in which are connected the contacts of the relay at theend of said track cir- 1

